It depends on your priorities. If you want to study your degree course seriously, then Vivekanand might be better for you because it is established earlier so has a large alumni base than SIES and way more experienced faculty.Otherwise if you want to prepare for competitive exams, then SIES will be good for you, because they are somewhat lenient in attendance rules. So you will get more time for preparation.
Last decision depends on you!
Good luck!